1. Field of the Invention
This invention relates in general to earth boring and in particular to earth boring bits of the type having rotatable cutters with earth disintegrating teeth.
2. Background Information
Earth boring bits fall generally into two categories: (1) drag bits with a variety of forms including those with synthetic or natural diamond used for cutting elements; (2) those with rotatable cutters having earth disintegrating teeth formed of steel and other suitable metals, such as sintered tungsten carbide.
The rotatable cone type bits have generally two or three cones. The three-cone bit has enjoyed the greater commercial success for a number of reasons, including the fact that they "run smooth". Two-cone bits tend to run rougher, a condition that generates vibrations in the bit and drill string that impedes drilling and tends to be detrimental to the drilling rig and equipment.
It is advantageous to utilize two-cone bits, if they can be made to run smooth, in some types of earth formations. The softer formations can be effectively drilled with two-cone bits, which usually have longer teeth or cutting elements.